Piercer point



Aug. 27, 1940. J. w. KELSO 2,212,690

PIERCER POINT Filed Jan. 25, 1938 FIG. 1.

O/P/Q/Nfil. C ON TOUR [mm afar.

JOHN W. KELSO,

Patented Aug. 27, 1940 PIERCER POINT John W. Kelso, East McKeesport, Pa., assignor to National Tube Company, a corporation of New Jersey Application January 25, 1938, Serial No. 186,878

1 Claim.

This invention relates to tube piercing mill piercer points, one of the objects being to provide a point having a longer service life than has been common.

A specific example of a piercer point embodying the principles of the invention is illustrated by the accompanying drawing, Figure 1 being a side View and Figure 2 a front end view.

More specifically, this point constitutes a cast body I of suitable contour and is characterized ,byhaving a mushroom-shaped nose portion 2 which provides a circumferential shoulder 3 adjacent the noseof the point. This shoulder functions to guide pierced metal away from the portion of the point supporting the nose 2 during the piercing. The advantage of this is that the portion of the point which must support the nose remains cooler than if the pierced metal contacted it. The reader no doubt appreciates that the blanks pierced by the point are heated to quite high temperatures and that, therefore, a longer service life results if the metal supporting the nose can be kept cooler, since it then retains more of its rigidity.

The mushroomed nose portion is formed by casting the point with a conventional contour; the usual sharper nose being subsequently heated to a forging temperature and upset by forging, the forging pressure being applied in a direction toward the rear of the point. The nose should be spherical to the shoulder 3, the point from there back following the conventional contour, if desired.

As shown by the drawing the spherical portion 35 2 is a segment of a sphere with the circular base tial shoulder while permitting the rest of the ical segment with the circular base of said segment having a radius from its center that is 30 PATENT OFFICE of this segment having a radius from its center that is greater than the thickness of this spherical segment. This causes the metal of a blank being pierced to engage the surface of this portion morenearly at right angles than is possible 5 when other shapes are used and results in causing a heavier than usual coating of scale to form on this portion. Such a heavier coating better insulates this portion than can be done by a thinner coating. Furthermore, this shape of the 10 nose provides a good offset to the circumferenpoint to be conventionally contoured, if desired. It has been found that a mushroomed nose portion that is spherical to the shoulder provided by reason of this shape, not only results in a point having a longer service life but lessens the power consumption of a mill using such a point.v

Another way to make the point is to cast it to the form ultimately desired. In such a case the forging operation is unnecessary. However, it is better to forge the nose to form because this works and compacts the metal in the proper direction to enable it to most successfully resist further deformation during use.

I claim:

A tube piercing mill piercing point having a mushroomed nose portion in the form of a sphergreater than the thickness of said segment, said base of said segment providing a peripheral shoulder offset from the adjacent peripheral portions of said point.

JOHN w. KELso. 

